In Christianity, the Devil is the personification of evil who rebelled against God in an attempt to become equal to God himself. He is depicted as a fallen angel, who was expelled from Heaven at the beginning of time, before God created the material world, and is in constant opposition to God. The devil is identified with several figures in the Bible including the serpent in the Garden of Eden, Lucifer, Satan, the tempter of the Gospels, Leviathan, and the dragon in the Book of Revelation. Early scholars discussed the role of the devil. Scholars influenced by neoplatonic cosmology, like Origen and Pseudo-Dionysius, portrayed the devil as representing deficiency and emptiness, the entity most remote from the divine. According to Augustine of Hippo, the realm of the devil is not nothingness, but an inferior realm standing in opposition to God. The standard Medieval depiction of the devil goes back to Gregory the Great. He integrated the devil, as the first creation of God, into the Christian angelic hierarchy as the highest of the angels (either a cherub or a seraph) who fell far, into the depths of hell, and became the leader of demons. Since the early Reformation period, the devil was imagined as an increasingly powerful entity, with not only a lack of goodness but also a conscious will against God, his word, and his creation. Simultaneously, some reformists interpreted the devil as a mere metaphor for human's inclination to sin and so downgraded the importance of the devil. While the devil played no significant role for most scholars in the Modern Era, he became important again in contemporary Christianity. At various times in history, some people such as the Cathars and the Bogomiles, as well as theologians like Marcion and Valentinus, believed that the devil was involved in creating the world. Today these views are not part of mainstream Christianity. Old Testament Satan in the Old Testament The Hebrew term () was originally a common noun meaning "accuser" or "adversary" that was applicable to both human and heavenly adversaries. The term is derived from a verb meaning primarily "to obstruct, oppose". Throughout the Hebrew Bible, it refers most frequently to ordinary human adversaries. However, 1 Samuel 29:4; 2 Samuel 19:22; 1 Kings 5:4; 1 Kings 11:14, 23, 25; Psalms 109:6 and Numbers 22:22, 32 use the same term to refer to the angel of the Lord. This concept